Display devices having numerical or alphabetical displays have been constructed employing film strips having numerals or letters on the film and with the film strips being supported such that selected numerals or letters are visible through windows in a supporting structure. The visible letters or numerals are changed by rolling the film strip past the window in the supporting structure. Examples of such devices are illustrated in the U.S. Trame Pat. No. 3,939,584, issued Feb. 24, 1976 and the U.S. Trame Pat. No. 4,095,359, issued June 20, 1978.
Attention is also directed to the U.S. Taber Pat. No. 3,426,115, issued Feb. 4, 1969, the U.S. Shapiro Pat. No. 1,999,133, issued Apr. 23, 1935, the U.S. Marette Pat. No. 1,553,906, issued Sept. 15, 1925, the U.S. Jeffreys Pat. No. 1,890,117, issued Dec. 6, 1932 and the U.S. Barnes Pat. No. 3,159,937, issued Dec. 8, 1964. Also of interest are the U.S. Bourseau Pat. No. 3,660,918, issued May 9, 1972, the U.S. Offensend et al. Pat. No. 3,100,356, issued Aug. 13, 1963, the U.S. Slavsky Pat. No. 2,951,301, issued Sept. 6, 1960 and the U.S. Coffey Pat. No. 2,588,803, issued Mar. 11, 1952.